$175 Class D amp--120 wpc

wushuliu · « **Reply #860 on:** 14 Mar 2010, 06:17 pm »

Quote from: Nick77 on 14 Mar 2010, 12:30 pm

Wushuliu is the mod as simple as just replacing the caps, no other changes to the board ie rectifier or such ??

Yes that's all I did, but check the bridge rectifier to make sure it's a 10 amp per deward's post above. The link by niteshade is to the 4700uf 'Heavy Duty' Supply for those who would rather not diy, but for that same money of course you could triple that or more with a good iron...

standub · « **Reply #861 on:** 14 Mar 2010, 07:20 pm »

Since I may pick up one of these class d amps I have a really stupid question, how did you guys attach the board to the metal cases. Did you just screw up through the bottom right into the risers? What about the toroidal transformer?

steve k · « **Reply #862 on:** 14 Mar 2010, 07:21 pm »

Quote

I've had a great time putting this all together from the NAD case to the one I'm presently working on. So now I would personally like to Thank Steve K for starting this post !!

You're quite welcome! It's been a wild ride. I'm still assembling my second amp and the modders are already modding the power supplies and the amp boards. Amazing. It will be interesting to hear the results of these upgrades and how they improve the sound. I'm still amazed at how well the stock ones sound in my system. I never would have believed they'd be replacing my beloved tube amps.

Time marches on.

steve

etcarroll · « **Reply #863 on:** 14 Mar 2010, 08:29 pm »

Quote from: Niteshade on 14 Mar 2010, 03:11 pm

Building one of these amps inside a computer would be a fascinating project! Not only that- but the ventilation would be perfect. You would have to use a full tower case. Ahh...one with a clear side!

Funny you say that, I just grabbed an old IBM Aptiva case out of the neighbor's trash for just this reason.

Now to decide on just what to build.

Steidl Guitars · « **Reply #864 on:** 14 Mar 2010, 09:58 pm »

Quote from: standub on 14 Mar 2010, 07:20 pm

how did you guys attach the board to the metal cases. Did you just screw up through the bottom right into the risers?

Correct.

Quote from: standub on 14 Mar 2010, 07:20 pm

What about the toroidal transformer?

Same, but no riser. All the hardware is provided with the kit.

jtwrace · « **Reply #865 on:** 14 Mar 2010, 10:30 pm »

Quote from: Steidl Guitars on 14 Mar 2010, 09:58 pm

Correct.

Same, but no riser. All the hardware is provided with the kit.

Just so you know, the "riser" is actually called a standoff. Just so you know the proper term if you ever have to source them.

J Payton · « **Reply #866 on:** 14 Mar 2010, 10:57 pm »

Has anyone attached a 12 volt trigger yet. If so I am curious how this is done.

I have (2 of the 600 watt TI amps) in an enclosure for surround duties and this would be a nice addon for that amp.

I have also put the 250 x 2 (8 Ohm) into a Hammond enclosure with a Hypex SMPS built for the UCD400. This makes for an excellent amp in a pretty small footprint (6 1/2 x 9 x 2 inches). I believe this amp sounds much better the the TI 600 watt amp.

I also built a Lighter Note LDR Preamp (Buildanamp.com) in a similar Hammond enclosure. This combination of the IR amp and the LDR volume control is truly unbelievable for the money.

I think it sounds as good if not better than the 2 UCD amps I have made. A UCD180 & UCD400 amp that both contained the H x R regulators in them.

DougSmith · « **Reply #867 on:** 14 Mar 2010, 11:01 pm »

I added a relay. Seems to work OK. I still want to get a power conditioner / sequencer, though because I use mine together with a DCX2496, which I cannot control automatically.

srb · « **Reply #868 on:** 14 Mar 2010, 11:05 pm »

Class D Audio said they were currently working on an audio signal trigger module, and when I inquired about a 12V trigger module, agreed that it would be a good idea and would try to have one of those in the near future as well.

Steve

pjchappy · « **Reply #869 on:** 15 Mar 2010, 07:21 pm »

Quote from: dewardh on 12 Mar 2010, 06:39 am

You may be spinning your wheels a bit worrying about power that you really don’t need. While the “1000 Watt” kit may be a little overhyped, especially considering the power supply, 4 channels at 125 Watts each into 8 Ohms is still a lot of power, and if you end up getting/building speakers with 4 Ohm drivers there is even more power available (though you’ll probably need to do some power supply improvement).

Regardless, I'm just curious about my previous question: Is it better / different to get 250 Watts per channel into 8 ohms with 2 bridged amp modules and 1 PS or just one stereo module and 1 PS?

Thanks!

Paul

jtwrace · « **Reply #870 on:** 15 Mar 2010, 07:36 pm »

Quote from: pjchappy on 15 Mar 2010, 07:21 pm

Regardless, I'm just curious about my previous question: Is it better / different to get 250 Watts per channel into 8 ohms with 2 bridged amp modules and 1 PS or just one stereo module and 1 PS?

Thanks!

Paul

It's fine to use two bridged amps per PS and tranny as far as I know. I've asked Tom about it and that's why the case will be made so you can do just that. Does it sound better seperate? Only you can answer that...

pjchappy · « **Reply #871 on:** 15 Mar 2010, 07:47 pm »

I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.

Again. . .just curious.

Paul

srb · « **Reply #872 on:** 15 Mar 2010, 07:59 pm »

Quote from: pjchappy on 15 Mar 2010, 07:47 pm

I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.

Since you are using them at 8 ohms, the fact that a bridged amp sees half the impedance probably doesn't make any difference in your application.

But who knows if one might change speakers in the future and end up with a 4 ohm pair. And although Tom @ Class D says all his IR amps, except the 250W @ 8 ohm, can run bridged for a 4 ohm load, International Rectifier's technical manual and other users say otherwise, so I think that configuration may be borderline acceptable.

I don't know how these particular Class D amps' characteristics vary from stereo to bridged mono, but many Class A/B amps I have come across in the past specify higher levels of distortion when bridged.

Steve

Nick77 · « **Reply #873 on:** 15 Mar 2010, 09:05 pm »

Quote from: pjchappy on 15 Mar 2010, 07:47 pm

I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.

Again. . .just curious.

Paul

I ran mine in bridged mode just to check out extra power and i wasnt that impressed with the results, not scientific or anything just didnt blow me away compared to stereo.

mjosef · « **Reply #874 on:** 15 Mar 2010, 09:13 pm »

From my very minuscule know-how/what, bridged amps usually suffer a little quality penalty vs unbridged (based on my use of Adcom/Hafler gear), I have zero experience with Digital Amps.

Over the past few days I have tried Shadowlight's amp in a few different positions, and I like what I hear, its different to what I am used to but it has responded well to better wiring/cables/conditioning. I am 92.5% sold.

I also noticed that it sounds more relaxed and effortless, after being on for 4-5hours.
I can see this replacing at least one amp in my HT setup.

jkelly · « **Reply #875 on:** 16 Mar 2010, 11:52 am »

Quote from: jkelly on 6 Mar 2010, 09:17 pm

My 250 x 2 has been shutting down if I play it fairly loud.
Anyone else getting shutdowns?

Tom's reply to my over heating issue:

"The problem was one of the adjustment pots must have knocked against
something and was not working properly. The amp was running at about twice
the speed it should."

Jeff

simoon · « **Reply #876 on:** 16 Mar 2010, 04:28 pm »

Quote from: srb on 15 Mar 2010, 07:59 pm

I don't know how these particular Class D amps' characteristics vary from stereo to bridged mono, but many Class A/B amps I have come across in the past specify higher levels of distortion when bridged.

Steve

I asked Tom at Class D this same question, even bringing up my previous unsatisfactory results bridging class A/B amps. and he told me that class D amps do not have that issue.

He said the sound is no different when bridged.

pumpkinman · « **Reply #877 on:** 17 Mar 2010, 02:49 am »

Birch plywood top

steve k · « **Reply #878 on:** 17 Mar 2010, 03:20 am »

Looks good! How is it fastened--from the sides? I hope to have mine in the box this weekend for a final pic of the twins. Tom is talking about a new Super D class of amps he's working on. He's sending me a demo.

He claims it has the same performance of his other IR amps except it projects a larger soundstage. I sure hope it all fits in my brand new boxes!! Film at 11.
steve

pumpkinman · « **Reply #879 on:** 17 Mar 2010, 10:26 am »

Quote from: steve k on 17 Mar 2010, 03:20 am

Looks good! How is it fastened--from the sides? I hope to have mine in the box this weekend for a final pic of the twins. Tom is talking about a new Super D class of amps he's working on. He's sending me a demo. He claims it has the same performance of his other IR amps except it projects a larger soundstage. I sure hope it all fits in my brand new boxes!! Film at 11.
steve

It will be held down with 1/2 dia. magnets set into the top and sides